The present invention relates to electrical energy storage and transforming devices and associated pulse-forming systems and, more particularly, to electrical energy storage and transforming devices that can receive and store an electrical charge and, when desired, deliver the so-stored charge to provide a desired output pulse, and, still more particularly, to systems, such as ignition systems for spark-ignition engines, utilizing such electrical energy storage and transforming devices for providing electrical output pulses.
Various devices, circuits, and systems are known for producing electrical energy pulses for diverse applications including the ignition system of spark-ignition internal combustion engines. The systems typically include a step-up transformer having inductively coupled primary and secondary windings. In such systems, electrical energy is applied to the primary winding and controlled to cause the desired output pulse across the secondary output winding. Prior systems have included switched-current systems and capacitive discharge systems. In the switched-current systems, a current flow is established through the primary winding to build a desired magnetic field and selectively interrupted in a step-wise manner by the opening of either a mechanical or semi-conductor switch to cause the desired output pulse. In the more sophisticated capacitive discharge ignition system, a capacitor in circuit with the primary winding is charged and, when an output pulse is desired, the capacitor is discharged through a triggerable switch to discharge the capacitively stored energy through the primary winding of the transformer to produce the desired output pulse. Capacitive discharge systems have many advantages in that a certain flexibility exists in most applications for the charging of the capacitor and in that the capacitor can retain its charge until an output pulse is desired. However, the capacitor is a separate physical component that is connected through conventional wiring to the primary of the pulse forming transformer; as can be appreciated, use of a physically separate capacitor in combination with the primary of the transformer adds a certain cost increment to the entire system and the need to rapidly switch a capacitively stored charge into an inductor can have a limiting effect on the upper output pulse repetition rate.